ABB Symphony Harmony Series, Instruction, Page: 164 / 402

Digital Output
WBPEEUI240751C0 4 - 9
Digital Output
For digital output capable blocks, channels are directly wired
in parallel to both I/O modules (Figs.
4-9 through 4-12 ). A
short across an output of one I/O module due to an I/O block
fault will not allow the output to switch off. There are no
detectable channel failures for the digital outputs of DIO-400
and DOT-100 blocks.
The DOT-120 block has readback circuitry to monitor actual
outputs. If there is a difference between the actual output and
the read back output, the channel will be marked as suspect.
For the DOT-120 block, failover will occur if the primary I/O
module has an output stuck closed, but the backup will be
unable to correct this condition.
Figure 4-6. AIN-220 Block - Current Mode (RFP Powered)
T 0 3 24 2 A
R E F 1
R E F 1
R E F 16
R E F 16
1
1
16
16
C H 1
C H 1
C H 16
C H 16
•
•
•
•
•
•
•
•
•
•
•
•
A IN -22 0 M O D U LE
A IN -22 0 M O D U LE
R E D U N DA N C Y L IN K
R E D U N DA N C Y L IN K
A M P
A M P
A M P
A M P
A /D
A /D
A /D
A /D
O P TO -
C O U P LE R
O P TO -
C O U P LE R
O P TO -
C O U P LE R
O P TO -
C O U P LE R
A
A
A
B
B
B
H N E T
C P U
A N D
H N E T
IN T E R FAC E
C P U
A N D
H N E T
IN T E R FAC E
+
+
+
+
R E D U N DA N T
A IN -2 20 B A S E
–
–
–
–
+
+ 24 V
–
+ 24 V
4-20 m A
LO O P